1. Field of the Invention
The present invention relates to a robot cleaner.
2. Background of the Invention
A cleaner is an apparatus configured to clean an indoor room by removing foreign materials. As the cleaner, generally used is a vacuum cleaner configured to suck foreign materials by using a suction force of a low pressure part. Recently, is being developed a robot cleaner capable of removing foreign materials from an indoor floor with autonomously moving through an automatic running function.
The robot cleaner includes a distance sensor configured to sense a distance of an obstacle such as furniture, office supplies, and a wall inside a cleaning area, and a wheel assembly configured to move the robot cleaner. The wheel assembly includes wheels provided at right and left sides of a robot cleaner main body, and a motor configured to rotate the wheels. The robot cleaner senses peripheral situations by the distance sensor, etc., and controls the motor, thereby performing indoor cleaning through autonomous running.
A suction means is provided in the robot cleaner main body, and a suction opening configured to suck dust is provided on a lower surface of the robot cleaner main body. An agitator configured to brush up dust of the bottom of the cleaning area is rotatably mounted to the suction opening. And, a filter configured to filter foreign materials included in air sucked from the bottom is provided on an air moving path inside the robot cleaner. While moving in the cleaning area, the robot cleaner autonomously performs a cleaning operation by sucking dust of the bottom into the robot cleaner main body and thereby collecting the dust into the filter, through a suction force by the suction means and rotations of the agitator. The collected dust is stored in a dust box inside the robot cleaner.
FIG. 1 is a side sectional view schematically showing a robot cleaner in accordance with the conventional art. Main components of the conventional robot cleaner will be explained in brief. A battery 10 having a rectangular shape is provided in the robot cleaner in a rechargeable manner so as to supply power for operating the robot cleaner. Due to a heavy weight, the battery is generally positioned on a central bottom surface of the robot cleaner, such that the robot cleaner performs a cleaning operation while smoothly moving in a balanced state. The dust box 20 configured to store collected dust therein is generally positioned above the battery 10. A suction fan 30 for providing a driving power to suck dust of the cleaning area is provided at the robot cleaner. The suction fan 30 sucks filth or dirt generated as the agitator 40 mounted to a bottom surface of the robot cleaner main body is rotated.
When compared with a general vacuum cleaner, the robot cleaner has a degraded suction force due to limitations of a size, a battery performance, etc. Accordingly, recently required is a robot cleaner having a strong suction force. For this, the motor for driving the suction fan 30 has to have an increased capacity. However, this may increase power consumption and noise. Furthermore, a large amount of battery is required for long usage time.
FIG. 2 is a view showing a lower part of the robot cleaner in accordance with the conventional art. Referring to FIG. 2, side brushes 50 configured to enhance a cleaning performance at areas adjacent to a wall surface, as well as the agitator 40 are provided at a lower part of the robot cleaner main body. The side brushes 50 are mounted at both sides of the lower part of the robot cleaner main body, and collect dust, etc. on the floor into the robot cleaner main body by being rotated centering around a rotation shaft disposed in upper and lower directions. In the conventional art, side brush driving motors 60 configured to drive the side brushes 50 are provided at the side brushes 50, respectively. Accordingly, an agitator driving motor has to be separately implemented from the motor for driving the plurality of side brushes. This may increase the number of components, and cause the robot cleaner to have a complicated inner structure.
In the conventional robot cleaner, a guide vane or a scroll for increasing a pressure is installed around the suction fan. However, this may cause the driving motor to be operated with a higher rpm, and cause a flow path to have a complicated structure. As a result, a flow resistance is increased, and thus noise is also increased.
More concretely, as shown in FIG. 3, air sucked in an axial direction of the suction fan is provided with a flowing force by the suction fan 31, and is guided by a guide vane 33 thus to move along the arrow of the drawing. Reference numeral 35 indicates a motor which provides a rotational force to the fan 31. In the case of installing the guide vane around the suction fan for pressure increase and air guidance, the suction fan has to be rotated with a high rpm so as to provide a sufficient suction force and flow amount. This may require high power consumption, and cause large noise.
FIG. 4 shows another example of the suction fan. Referring to FIG. 4, air sucked in an axial direction of the suction fan is provided with a flowing force by the suction fan 41, and is guided by a scroll 43 thus to be discharged to one side. Reference numeral 45 indicates a motor which provides a rotational force to the suction fan 41. In the case of using the scroll, the suction fan has a large size due to a structure of the scroll. Furthermore, if the suction fan is rotated with a high speed, large noise may be caused.